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[
International C. elegans Meeting,
1997]
Host cell factor (HCF) is a cellular factor involved in initiating herpes simplex virus (HSV) gene expression upon HSV infection by promoting complex assembly between the viral transactivator VP16 and the cellular POU homeodomain protein Oct-1. Recent studies have suggested that HCF is involved in regulating cell growth and proliferation. Consistent with this hypothesis, during development HCF is expressed at high levels in human embryonic tissues, in which cells are actively dividing, and at low levels in most adult tissues. More importantly, a point mutation in the N-terminal region of HCF that interacts with VP16 leads to a G0/G1 cell cycle arrest in baby hamster kidney cells.
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Neuron,
2018]
Animals' movements actively shape their perception and subsequent decision making. In this issue of Neuron, Liu etal. (2018) show how C.elegans nematodes steer toward an odorant: a dedicated interneuron class integrates oscillatory olfactory signals, generated by head swings, with corollary discharge motor signals.
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J Cell Biol,
2020]
In this issue, Liu et al. (2019. J. Cell. Biol.https://doi.org/10.1083/jcb.201907067) find that the inhibition of mitochondrial ribosomes in combination with impaired mitochondrial fission or fusion increases C. elegans lifespan by activating the transcription factor HLH-30, which promotes lysosomal biogenesis.
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MicroPubl Biol,
2021]
C. elegans males that have come into close proximity of hermaphrodites initiate copulatory behavior comprising at least five different steps termed response, turning, location of vulva, spicule insertion and sperm transfer (Loer and Kenyon 1993, Liu and Sternberg 1995, Chute and Srinivasan 2014). Mutations specifically affecting different steps have been isolated and characterized (Barr and Sternberg 1999, Hajdu-Cronin et al. 2017, Liu et al. 2017). However, our understanding of the molecular mechanisms acting in the neurons controlling copulation is far from complete. During the response step, males that have sensed the presence of a hermaphrodite move backwards in such a way that the males tail fan glides along the surface of the hermaphrodite until the tail reaches the vulva (or head or tail) (Loer and Kenyon 1993, Liu and Sternberg 1995, Sherlekar and Lints 2014). Response behavior is regulated by ciliated neurons in the tail whose dendrites lie in sensory rays within the fan (Liu and Sternberg 1995). If a male reaches the end of the hermaphrodite without having found the vulva, it executes a turn during which the tail bends tightly ventrally so that contact is established between the ventral surface of the fan and the other side of the intended mate (Loer and Kenyon 1993, Liu and Sternberg 1995). The ability to execute turns efficiently is dependent upon serotonergic neurons in the posterior ventral nerve cord (the CP neurons) and on their ability to produce serotonin (Loer and Kenyon 1993, Carnell et al. 2005). Serotonin stimulates the diagonal muscles in the tail to induce curling ventrally by stimulating a serotonin receptor, SER-1 (Loer and Kenyon 1993, Carnell et al. 2005). However, how serotonin affects diagonal muscles and ventral turning is not fully understood.
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Cell Metab,
2013]
All physiological functions decline with age, but which changes are primary and which are secondary is not always clear. Liu et al. (2013), examining functional changes in the muscles and motor neurons of C. elegans, suggest that when it comes to locomotion, it is the nervous system that shows earlier age-related deterioration.
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[
International C. elegans Meeting,
2001]
In order to examine the process of sulfation in C. elegans, sulfation was inhibited chemically using sodium chlorate, and genetically using the process of RNA-mediated interference (RNAi). Sodium chlorate inhibition during early larval stages resulted in a dose-dependant developmental delay. BLAST searches of characterized sulfotransferases against the worm genome resulted in the identification of 4 putative sulfotransferases: C34F6.4 and F08B4.6 (previously identified: [1] and [2]), F40H3.5, and Y34B4A.e. RNAi of the putative N-deacetylase/N-sulfotransferase F08B4.6 resulted in "stacking" of eggs in the gonad, along with eggs laid at the 2- and 4-celled stage. RNAi of the putative hexuronic 2-O sulfotransferase C34F6.4 resulted in a shortened, bulbous gonad. These initial results indicate that sulfation may be important during development of C. elegans. [1] Shworak, NW, Liu, J, Fritze, LMS, Schwartz, JJ, Zhang, L, Logeart, D, Rosenberg, RD. JBC 272: 28008-19 (1997). [2] Kobayashi, M, Sugumaran, G, Liu, J, Shworak, NW, Silbert, JE, Rosenberg, RD. JBC 274: 10474-80 (1999).
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[
Development,
2024]
Germ granules have been hypothesized to deliver mRNAs of germ cell fate determinants to primordial germ cells. Now, a new study in Development finds that many mRNAs enriched in germ granules are not involved in germline development in Caenorhabditis elegans. To find out more about the story behind the paper, we caught up with first author Alyshia Scholl, second author Yihong Liu and corresponding author Geraldine Seydoux, Professor at Johns Hopkins University School of Medicine.
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[
West Coast Worm Meeting,
2002]
C. elegans male mating behavior involves the proper execution of a series of sub-behaviors culminating in the transfer of sperm to the hermaphrodite (Liu, KS and Sternberg, PW. 1995. Neuron 14:79-89). These sub-behaviors are: Response to hermaphrodite, backing, turning, vulval location, spicule insertion and sperm transfer. We are analyzing the genetic control of this stereotyped behavior as it may provide insight into sensory perception and nervous system function.
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[
EMBO J,
2013]
A key finding of modern ageing research is that our limitation in lifespan is more than the result of accumulated organismal decay. Lifespan is regulated by genetically defined chemosensory and endocrine pathways, which integrate signals that reflect the internal and external status of the animal. New findings by Liu and Cai unravel a role for the environmental gases oxygen and carbon dioxide in the regulation of lifespan homeostasis and thus a novel function of oxygen-chemosensory neurons in C. elegans.
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[
Science,
1996]
The degenerin family of proteins in Caenorhabditis elegans is homologous to subunits of the mammalian amiloride-sensitive epithelial sodium channels. Mutations in nematode degenerins cause cell death, probably because of defects in channel function. Genetic evidence was obtained that the
unc-105 gene product represents a degenerin homolog affecting C. elegans muscles and that this putative channel interacts with type IV collagen in the extracellular matrix underlying the muscle cell. This interaction may serve as a mechanism of stretch-activated muscle contraction, and this system could provide a molecular model for the activation of mechanosensitive ion channels.AD - Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA.FAU - Liu, JAU - Liu JFAU - Schrank, BAU - Schrank BFAU - Waterston, R HAU - Waterston RHLA - engSI - GENBANK/J04694SI - GENBANK/M23704SI - GENBANK/M67507SI - GENBANK/U07224SI - GENBANK/U07888SI - GENBANK/U22327SI - GENBANK/X56979SI - GENBANK/X76730SI - GENBANK/Y00706ID - GM23883/GM/NIGMSPT - Journal ArticleCY - UNITED STATESTA - ScienceJID - 0404511RN - 0 (Helminth Proteins)RN - 0 (Sodium Channels)RN - 0 (Unc-105 protein)RN - 9007-34-5 (Collagen)SB - IMSB - S